Microscopic features of the regeneration of white pulp in autotransplanted spleens in rats.

The process of regeneration of white pulp in autotransplanted splenic tissue, implanted into a pocket made by the greater omentum in rats, was investigated histologically and immunohistochemically. Three days after transplantation, almost all implants were necrotic. At day 7, viable splenic tissue had gradually regenerated at the periphery of the implants. At day 10, lymphocytes accumulated around the arterioles. The accumulations resembled the periarteriolar lymphoid sheath of normal spleens in structure, but consisted mainly of B-lymphocytes, with a few scattered T-lymphocytes. However, by week 2, the localization peculiar to T- and B-lymphocytes became definite, and follicular dendritic cells were simultaneously observed in the lymph follicles. This regeneration of the white pulp in the autotransplanted spleens differed from the formation of the white pulp during ontogeny and during recovery after spleen irradiation.